This invention relates to a nuclear power plant having a safety enclosure which encloses the nuclear reactor. A high pressure is potentially possible on the inside of the enclosure and must be contained against escape to the outside. The fuel element storage basin is also located on the inside of the safety enclosure beside the reactor so that the reactor's fuel elements can be changed expeditiously.
More particularly, the invention is concerned with a light-water reactor, particularly a pressurized-water reactor, having a pressure containment system requiring the safety enclosure. To change fuel elements, a space above the reactor and the fuel element storage basin is flooded with water. The fuel elements are transported to and from the storage basin while immersed under water in fuel element transport vessels, so that the after-decay heat is removed and shielding is provided. People must pass into and from the safety enclosure with the large and heavy transport vessels, the safety enclosure having an adequately large lock for this purpose. Remote-controlled equipment inside of the safety enclosure is provided for moving the fuel elements between the reactor and storage basin, but special crane equipment is required to handle the transport vessels. The lock, proportioned to pass the people and transport vessels, involves operational difficulties.